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How Are Coolers Made: A Comprehensive Guide

November 05, 2023 5 min read

How Are Coolers Made: A Comprehensive Guide - Maria's Condo

Coolers are essential for keeping our food and drinks cool during outdoor activities and trips. But have you ever wondered how these coolers are made? In this comprehensive guide, we will explore the various manufacturing processes, materials, and technologies used in the production of coolers. From understanding the insulation techniques to comparing rotomolding and injection molding methods, we will delve into the fascinating world of cooler production.


I. The Importance of Insulation in Coolers

When it comes to coolers, insulation is key. The primary goal of a cooler is to keep the heat out and maintain a cold environment for extended periods. Understanding the science behind insulation is crucial in appreciating the design and functionality of coolers.

A. The Thermodynamics of Heat Transfer

To comprehend the concept of insulation, we need to grasp the fundamentals of heat transfer. Heat is the motion of molecules, and the quicker they move, the hotter the substance becomes. In contrast, cold is the absence of heat. Therefore, the primary objective of a cooler is not to keep the "coldness" in, but to prevent heat from entering.

B. The Role of Insulation

Insulation in coolers works by reducing heat transfer through conduction, convection, and radiation. It acts as a barrier between the interior and exterior environments, slowing down the movement of heat molecules. By utilizing effective insulation materials and techniques, coolers can maintain low temperatures and prolong ice retention.

II. The Manufacturing Processes: Rotomolding vs. Injection Molding

The production of coolers involves sophisticated manufacturing processes that ensure durability, strength, and insulation efficiency. Two common methods utilized in cooler production are rotomolding and injection molding. Let's explore the characteristics and differences of these processes.

A. Rotomolding: The Gold Standard

Rotomolding, also known as rotational molding, has long been the industry standard for high-end coolers. This manufacturing process involves the use of molds and high-density polyethylene (HDPE) plastic.

  1. The Thermoforming Process

    • Raw material: Expandable polystyrene beads (EPS)
    • Pre-expansion: Beads are heated with steam, causing them to expand
    • Aging: Expanded beads cool and stabilize
    • Injection into molds: Beads are injected into aluminum molds
    • Rotational heating: Steam enters the mold, reheating the beads
    • Fusion and cooling: Beads fuse into a single shape and cool
  2. Advantages of Rotomolding

    • Thick and even walls: Provides strength and stress resistance
    • Excellent insulation: Allows for extended ice retention
    • Durability: Withstands rugged conditions and impacts
    • Limited stress marks: Low-pressure molding minimizes stress-related issues

B. Injection Molding: Reducing Weight without Sacrificing Performance

Injection molding is an alternative manufacturing process that offers lighter coolers with complex designs. It involves injecting plastic into molds under high pressure.

  1. The Injection Molding Process

    • Mold creation: Strong and expensive molds are required
    • Plastic injection: Molten plastic is injected into molds
    • Cooling and removal: Plastic solidifies and is removed from the mold
    • Dual-wall construction: Interior and exterior walls are created separately
    • Polyurethane insulation: Insulation is added between the walls
    • Design flexibility: Complex designs, ridges, and fins can be incorporated
  2. Advantages of Injection Molding

    • Weight reduction: Uses less plastic, resulting in lighter coolers
    • Versatile designs: Allows for intricate features and aesthetics
    • Efficient production: High-pressure molding enables faster production
    • Comparable insulation: Polyurethane foam provides excellent thermal efficiency

III. Materials Used in Cooler Production

The materials used in cooler production play a crucial role in insulation, durability, and overall performance. Let's explore the primary materials employed in both rotomolded and injection molded coolers.

A. Rotomolded Coolers

Rotomolded coolers typically use high-density polyethylene (HDPE) plastic for their durable exterior shells. HDPE is known for its impact resistance, strength, and ability to withstand rugged conditions. Additionally, rotomolded coolers feature polyurethane foam insulation, renowned for its thermal efficiency.

B. Injection Molded Coolers

Injection molded coolers often utilize a combination of materials. The exterior shell is made of durable plastic, while the interior and exterior walls are created separately and then fitted together. Polyurethane foam insulation is added between these walls to ensure optimal thermal performance.

IV. Comparison and Evaluation of Manufacturing Methods

To determine the advantages and disadvantages of rotomolding and injection molding, we need to consider various factors, such as cost, design complexity, production time, manufacturing stress, waste, and weight.

A. Cost

Rotomolding has the advantage in terms of initial cost. The low-pressure nature of the process allows for the use of less expensive molds. Injection molding, on the other hand, requires stronger and more expensive molds due to the high-pressure requirements.

B. Design Complexity

Injection molding takes the lead in design complexity. The high-pressure injection ensures that the plastic fills every intricate detail of the mold, allowing for more intricate designs, ridges, and fins.

C. Production Time

Injection molding offers faster production times due to the high-pressure process. Rotomolding, while providing superior insulation and durability, takes longer to produce each piece.

D. Manufacturing Stress

Rotomolding minimizes manufacturing stress, resulting in fewer stress marks on the plastic. The low-pressure nature of the process ensures uniform distribution of the plastic, reducing potential flaws.

E. Waste

Both rotomolding and injection molding generate minimal waste. Excess plastic, known as flashing, can be recycled and used in the production of other products, minimizing material waste.

F. Weight

Injection molding excels in weight reduction. By utilizing less plastic, injection molded coolers can be up to 30% lighter than their rotomolded counterparts, making them easier to transport.

V. Conclusion: The Best of Both Worlds

In the debate of rotomolding vs. injection molding coolers, it is clear that both methods have their advantages. Rotomolding offers superior insulation, durability, and stress resistance, while injection molding provides lighter weight and intricate design capabilities. Ultimately, the choice between the two depends on the specific needs and preferences of the consumer.

Regardless of the manufacturing method, high-quality coolers like those produced by Pelican come with an unmatched lifetime warranty, ensuring long-lasting performance. Whether you opt for a rotomolded or injection molded cooler, you can trust in the craftsmanship and dedication that goes into creating these essential outdoor companions.

Remember, when selecting a cooler, consider the insulation, material quality, and design features that best suit your needs. With the right cooler, you can enjoy extended ice retention and keep your drinks and food cool even in the harshest outdoor conditions.


  1. What materials are typically used in the construction of coolers, and how do they contribute to their cooling capabilities?

  2. Can you describe the manufacturing process of the insulation layer in coolers and its importance in maintaining temperature?

  3. What are the key design considerations when creating a durable and efficient cooler, and how do manufacturers ensure quality in their products?

Marias Condo
Marias Condo

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